(1) Field of the Invention
The present invention relates to a television signal transmission system, and more particularly, to a television signal transmission system in which a wide-band television video signal is transmitted in a frequency band narrower than the frequency band of the television video signal itself and is regenerated in a television receiver.
(2) Description of the Prior Art
Hitherto, the standard television signal employs a transmission frequency band which is limited according to standards; hence, there is a limit in the resolution of the picture which is reproduced from the television signal in a television receiver.
To improve the resolution of the reproduced television picture, it is necessary to widen the transmission frequency band thereby to make it possible to enlarge the frequency band for the signal. More specifically, while the signal frequency band is specified to be 4.2 MHz in the standard NTSC television system, it is necessary to transmit the television signal in a frequency band of 6.0 MHz, for example, if the resolution is to be improved.
However, such a change in the signal frequency bandwidth requires modification of all of the standard broadcasting equipment, television receivers, channel frequency assignments and so forth. Such modifications can be made technically but are extremely difficult to realize in actual practice.